The invention concerns a process for operating a strip-casting machine, in which molten metal is poured between two rotating casting rolls, and a gaseous film is formed between the surface of each casting roll and the strip skin forming on the molten metal at the surface of the casting roll, with the gas being introduced into the inerting chamber located above the metal bath. The invention also concerns a jacket ring for the casting roll of the strip-casting machine.
In a casting roll of the type described in document EP-A-0 309 247, uniformly distributed depressions are incorporated in the surface of the roll and are spaced some distance apart. These depressions result in the formation of gas bubbles during casting and thus prevent primary cracks in the strip skin of the solidified molten metal and, in addition, are intended to provide sufficient thermal conductivity. However, these depressions also lead to a corresponding roughness of the surface of the cast metal strip. Furthermore, these casting rolls must be refinished after relatively short times, since the depressions, which can measure up to 100 micrometers, decrease in size as the surface of the roll wears. In addition, these depressions or textures, in which dirt accumulates relatively fast, must be frequently cleaned.